This invention relates generally to antenna mounts, and in particular to a mount for securing a portable antenna to the top of a mast.
Global Positioning System (GPS) is a space-based positioning and velocity system for determining the worldwide position and velocity of a craft, such as a wheeled or tracked vehicle, an amphibian, or watercraft. GPS has three major segments: space (transmitting satellites), control, and user equipment (receiver). The GPS is predicated upon accurate and continuous knowledge of the spatial position of each satellite in the system, with respect to time and distance from a transmitting satellite to the user. Each satellite transmits its unique ephemeris data. This data is periodically updated by a master control station based upon information obtained from widely dispersed monitor stations. The GPS receiver automatically selects appropriate signals from the three or four satellites best in view based on optimum satellite-to-user geometry. It then solves time of arrival difference quantities to obtain the distance between user and satellites. This information establishes the user position with respect to the satellite system. A time correction factor then relates the satellite system to earth coordinates. The user equipment measures four independent pseudo ranges and range rates and translates these to three-dimensional position and velocity.
The receiver includes a standardized antenna mounted on the craft. The GPS antenna has a smooth generally cylindrical body and a coaxial electrical connector extending downward from its lower end which engages with a connector on a cable leading to the receiver. The GPS antenna may be mounted on a mast secured to the craft. The antenna may be susceptible to damage by excessive vibration to the craft or by impact to the antenna by, for example, tree branches. GPS antenna have often been supported only by the connection of the connectors. A problem associated with supporting a GPS antenna only by its connector is that the connector is likely to break if the craft is excessively shocked or vibrated or if the antenna is struck by an object or impacted by a sudden gust of wind. Such breakage renders the system inoperable. Also, replacement GPS antenna are expensive.